1. Field of the Invention
The present invention relates to a semiconductor built-in millimeter-wave band module, and more particularly relates to a semiconductor built-in module in which a semiconductor device operating at a micrometer-wave band or a millimeter-wave band (hereinafter referred to as “semiconductor device operating at a millimeter-wave band”) is arranged inside of an electrical insulating substrate.
2. Related Background Art
In recent years, with a demand for miniaturized electronic equipment having higher performance, circuit components with ever higher density and higher functionality have been demanded. To this end, a circuit board commensurate with the circuit components with higher density and higher functionality has been requested. Especially, as a method for packaging circuit components including a semiconductor device densely, a circuit component built-in module capable of including a semiconductor device therein is proposed by using an electrical insulating substrate (hereinafter also referred to as “insulating substrate”) made of a mixture containing an inorganic filler and a thermosetting resin (JP 11(1999)-220262 A and JP-3051700 B).
Meanwhile, a package that allows heat generated from a semiconductor device operating at a millimeter-wave band to dissipate to the outside by effectively transmitting the heat, in general, has a configuration in which a semiconductor device is mounted in a concave portion of a concavity ceramic package inside of which a plurality of wiring layers are provided and a cavity is provided using a sheet-type lid. In another configuration a semiconductor device is mounted on a flat multilayered substrate and a cavity is provided using a lid with a concave portion between this lid and the flat multilayered substrate. In addition, as an example of a higher heat dissipation efficiency, a method in which a surface of a material with a high thermal conductivity contacts with a surface of a semiconductor device is proposed (JP-2856192B).
However, the conventional configuration in which a surface of a material with a high thermal conductivity contacts with a surface of semiconductor device has a problem in that when the semiconductor device is packaged on a wiring board in a face-up manner, an active surface of the semiconductor device contacts with the material with a high thermal conductivity and is covered with the same, which increases an effective dielectric constant at the active surface as compared with the case of contacting with air. This causes a change in the properties of the semiconductor device.
When trying to downsize a semiconductor device operating at a millimeter-wave band, the conventional configurations cannot realize a sufficient heat dissipation capability because heat cannot dissipate effectively, which causes a problem of a deterioration in reliability of a module including the device therein. Therefore, it is difficult to improve the heat dissipation efficiency while downsizing the semiconductor device operating at millimeter-wave band and other circuit components.